KR102170002B1 - Transmission device, transmission method, reception device, and reception method - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a transmission device and a transmission method, and a reception device and a reception method for suppressing redundancy of a header in packet communication. An area indicating the packet length in the packet header is set according to the payload size of the input packet. The header of the baseband packet includes type identification information for identifying the type of the input packet or stream, and a minimum fixed length header having information on the packet length of the input packet or stream stored in the payload of the baseband packet.

Description

A transmitting device and a transmitting method, and a receiving device and a receiving method {TRANSMISSION DEVICE, TRANSMISSION METHOD, RECEPTION DEVICE, AND RECEPTION METHOD}

TECHNICAL FIELD The present technology relates to a transmission device and a transmission method, and a reception device and a reception method. In particular, the number of bits for storing packet length information in the header is variable according to the transmission packet length. The present invention relates to a transmission device and a transmission method, and a reception device and a reception method capable of transmitting and receiving an input packet at high speed with high efficiency by suppressing the tension.

With the digitization of broadcast signals and the development of communication technologies, it has become possible to transmit content including video and audio in both broadcast and communication.

While broadcasting can stably transmit content to multiple users at the same time, it can communicate only in one direction. On the other hand, in communication, although content can be transmitted in both directions according to a request, the content cannot be stably transmitted due to congestion of the network.

Accordingly, even in broadcasting, a technique for realizing two-way communication while enabling the transmission of various types of contents by transmitting contents using IP packets widely used in communication has been proposed. As one of such technologies, for example, DVB-T2 (Digital Video Broadcasting-Terrestrial Second Generation) is mentioned (see, for example, Non-Patent Document 1).

In addition, a broadcast method capable of transmitting IP packets has been proposed, for example, advanced BS (Broadcasting Satellite) digital broadcasting, ISDB-TSB (Integrated Services Digital Broadcasting-Terrestrial Sound Broadcasting), DVB-S2 (Digital Video Broadcasting). -Satellite Second Generation) and ATSC-DTV (Advanced Television System Committee-Digital Television).

ETSI EN 302 755 V1.3.1 (2012-04)

In the broadcast system capable of transmitting the above-described IP packet, for example, in the case of advanced digital BS broadcasting, ISDB-T, DVB-T2, DVB-S2, and ATSC-DTV, TLV (Type Length Value) is a multi-time format, respectively. Packets, Transport Stream (TS) packets, (both DVB-T2 and DVB-S2) Generic Stream Encapsulation (GSE) packets and TS packets are used. Here, for ISDB-TSS and ATSC-DTV using TS packets, the IP packet is a TS packet by a method such as ULE (Unidirectional Lightweight Encapsulation) and ATSC-MPE (Multi-Protocol Encapsulation) when transmitting an IP packet. Encapsulated in and transmitted. In addition, in other methods, IP packets are transmitted without using TS packets.

When a broadcast content packet and an IP packet are mixed and transmitted, packets of various packet lengths are distributed. In other words, the packet length of the IP packet that is considered to be the minimum including control information, etc. is 40 bytes (B) in TCP/IP (Transmission Control Protocol/Internet Protocol), and UDP/IP (User Datagram Protocol/Internet Protocol). In the case, it is 28 bytes (B). In addition, the TS packet is fixed to 188 bytes, for example. In addition, as an intermediate packet length, there are also IP packets of about 576 bytes, on the other hand, the MTU (Maximum Transmission Unit) of the IP packet is also 1500 bytes.

As described above, the packet length of the IP packet may be various. However, in the broadcasting method that can transmit IP packets, statistics on the packet length actually used are shown, and as a result, the frequency of use of packets of the minimum and maximum sizes is the highest, and the use of medium-sized packets is relatively low. Became.

Therefore, in a broadcasting method including an IP packet, if the number of bits is set so that information of the maximum packet length can be stored in the header, when transmitting an IP packet of about several bytes, the upper bit among the bits set for the packet length in the header There are many packets that are not used.

That is, in reality, despite the frequency of circulation of packets with small packet lengths, if the number of bits capable of storing information corresponding to the maximum packet length is prepared in the header, packets of small packet lengths with relatively high usage frequency In the case of, the high-order bit is not used. As a result, in a circulating packet, there is a fear that the header is redundant.

The present technology has been made in consideration of such a situation, and in particular, by setting the number of bits for storing packet length information in the packet header according to the packet length, and realizing use according to the packet length, The redundancy of the header is reduced and communication efficiency is improved.

A transmission apparatus according to the first aspect of the present technology includes a baseband packet generation unit that generates a baseband packet from an input packet or stream, a baseband frame generation unit that generates a baseband frame from the baseband packet, and the baseband And a transmission unit for transmitting a frame, wherein the header of the baseband packet includes type identification information for identifying the type of the input packet or stream, and a packet length of the input packet or stream stored in the payload of the baseband packet Contains the minimum fixed length header with information of.

When the type identification information is the input packet or the type of the stream is an IP packet, in the minimum fixed length header, in addition to the type identification information, minimum fixed length identification information for identifying whether the input packet length is a minimum fixed length, and The minimum input packet length information may be included as the input packet length information.

When the minimum fixed length identification information indicates that the input packet length is not the minimum fixed length, the header may further include a variable length header in addition to the minimum fixed length header, and the variable length header When the lower bit of the input packet length is used as the minimum input packet length and the minimum input packet length information, variable length packet length information including the upper bit, and an additional header added to the variable length header It is possible to include an additional header flag indicating presence or absence.

When the segmentation flag indicates that the input packet or stream is segmented to form a baseband packet, a segmentation flag header includes a flag ID identifying the segmentation flag and information identifying the segmented baseband packet. You can try to include a flag counter to be used.

When the additional header flag indicates that the additional header is present, the header may further include an additional header in addition to the minimum fixed length header and the variable length header, and in the additional header, the additional header Includes additional header identification information identifying the type of header, extended packet length information including a bit higher than the variable length packet length information representing the input packet length, and additional information header flag indicating the presence or absence of an additional information header You can do it.

When the additional information header flag indicates that the additional information header is present, the additional information header including predetermined information in addition to the minimum fixed length header, the variable length header, and the additional header is included in the header. You can try to include more.

When the additional header identification information indicates that the label information, in addition to the minimum fixed length header, the variable length header, and the additional header, the additional information header including predetermined label information is further included in the header. can do.

The baseband packet generation unit may identify a type of the input packet or stream, register the identified type to a type identification unit, and generate a baseband packet according to the identified type.

The minimum input packet length information may be information of a minimum fixed length including bit information obtained by offsetting the number of bits corresponding to the minimum packet size.

When the type identification information is a transport stream packet, an empty packet identifying whether a baseband packet is formed by deleting an empty packet from among the transport stream packets in addition to the type identification information in the minimum fixed length header As the deletion information and information on the length of the input packet included in the baseband packet, information on the number of transport stream packets indicating the number of transport stream packets may be included.

If the packet deletion information is information indicating that a baseband packet is formed by deleting empty packets from among the transport stream packets, the header further includes information indicating the number of deleted empty packets. I can.

In the type identification information, unspecified protocol information indicating that a protocol other than information specifying a protocol of the input packet or stream may be included. When the type identification information is the unspecified protocol information, the header , In addition to the minimum fixed-length header, predetermined protocol information specifying a predetermined protocol may be further included.

The transmission method of the first aspect of the present technology includes the steps of generating a baseband packet from an input packet or stream, generating a baseband frame from the baseband packet, and transmitting the baseband frame, wherein the baseband The header of the packet includes type identification information for identifying the type of the input packet or stream, and a minimum fixed length header having information on the packet length of the input packet or stream stored in the payload of the baseband packet.

A receiving apparatus according to the second aspect of the present technology includes a receiving unit for receiving a signal including a transmitted baseband frame, a baseband packet generator for generating a baseband packet from the received baseband frame, and the baseband packet An input packet generator for generating an input packet or stream from, and the header of the baseband packet includes type identification information for identifying the type of the input packet or stream, and the input stored in the payload of the baseband packet Includes a minimum fixed length header with information on the packet length of a packet or stream.

The receiving method of the second aspect of the present technology includes receiving a signal including a transmitted baseband frame, generating a baseband packet from the received baseband frame, and generating an input packet or stream from the baseband packet. Including a step, wherein the header of the baseband packet has type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. Contains the minimum fixed length header.

In the first aspect of the present technology, a baseband packet is generated from an input packet or stream, a baseband frame is generated from the baseband packet, the baseband frame is transmitted, and in a header of the baseband packet, the A minimum fixed length header having type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet is included.

In the second aspect of the present technology, a signal including a transmitted baseband frame is received, a baseband packet is generated from the received baseband frame, an input packet or stream is generated from the baseband packet, and the The header of the baseband packet includes a minimum fixed length header having type identification information identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. do.

According to the first and second aspects of the present technology, transmission/reception of various types of input packets or streams is realized by a single stream, and redundancy of the packet header is suppressed even when input packets or streams of various sizes are transmitted/received. Thus, it becomes possible to transmit and receive with high efficiency.

1 is a diagram for explaining a configuration example of a transmission device to which the present technology is applied.
2 is a diagram for explaining a configuration example of a reception device to which the present technology is applied.
3 is a diagram for explaining an example of the configuration of a header of BBP.
4 is a diagram for explaining a configuration example of BBP and BBF in a variable length mode.
5 is a diagram illustrating the frame length of the BBF.
6 is a diagram illustrating a specific configuration example of a header of BBP.
7 is a diagram for explaining an example of the configuration of BBP and BBF in the short packet mode.
8 is a diagram for explaining an example of a configuration of a header of a BBP in a short packet mode.
9 is a diagram for explaining an example of a configuration of a header of a BBP in a split mode.
10 is a diagram for explaining an example of a configuration of a header of a BBP in an additional variable length mode.
11 is a diagram for explaining an example of the configuration of BBP and BBF in the case of TS mode and not the empty packet deletion mode.
12 is a diagram for explaining a configuration example of a header of a BBP in the case of a TS mode and not an empty packet deletion mode.
Fig. 13 is a diagram for explaining a configuration example of the BBF in DVB-T2 in the case where the TS mode is not the empty packet deletion mode.
14 is a diagram for explaining a configuration example of a BBP in a TS mode and an empty packet deletion mode.
15 is a diagram for explaining an example of the configuration of the BBF in DVB-T2 in the TS mode and in the empty packet deletion mode.
16 is a diagram for explaining an example of the configuration of a header of a BBP when transmitting a bit stream packet.
17 is a diagram illustrating a configuration example of the BBH of the BBF.
Fig. 18 is a diagram illustrating an example of the configuration of the BBH of the BBF in DVB-T2.
Fig. 19 is a flowchart for explaining transmission/reception processing by the transmission device and the reception device of the present technology.

[Configuration example of sending device]

1 shows a configuration example of an embodiment of a transmission device to which the present technology is applied. The transmission device 11 receives various input packets, which are broadcast signals, which are composed of other packets such as TS (transport stream) packets, IP packets, and bit stream packets, as described with reference to FIG. To the device. At this time, the transmission device 11 generates a baseband packet (BBP) by integrating a plurality of input packets. At this time, the transmission device 11 prepares a plurality of bits as the number of bits required for expressing the packet length in the header of the BBP, and configures the BBP header by switching according to the packet size of the BBP, Suppresses the redundancy of the BBP header.

More specifically, the transmission device 11 includes a BBP generation unit 31, a BBF (baseband flame) generation unit 32, a BBF scrambler 33, and a transmission unit 34. Further, the BBF generation unit 32 includes a BBH (BBF header) adding unit 41.

The BBP generation unit 31 identifies the type of the input packet, integrates a plurality of input packets according to the identified type to generate a BBP, and supplies the generated BBP to the BBF generation unit 32. At this time, the BBP generation unit 31 can switch and set the number of bits for expressing the packet length of the BBP in the header of the BBP into a plurality of types, and switch the number of bits according to the packet length of the input packet. do. As a result, it becomes possible to suppress the redundancy of the header caused by the change in the packet length of the BBP. Further, details of the BBP generated by the BBP generation unit 31 will be described later with reference to FIG. 3 and later.

The BBF generation unit 32 generates a BBF by integrating required BBPs so as to have a predetermined frame length, and supplies the generated BBF to the BBF scrambler 33. At this time, the BBF generation unit 32 controls the BBH addition unit 41 to generate and add the BBH header of the BBF.

The BBF scrambler 33 scrambles the BBF generated by the BBF generation unit 32 and supplies it to the transmission unit 34.

The transmission unit 34 transmits the scrambled BBF to the reception device through a network or a broadcasting network.

[Configuration example of receiving device]

FIG. 2 shows a configuration example of a receiving device that receives the BBF transmitted from the transmission device 11 described with reference to FIG. 1, generates a BBP from the BBF, and generates and outputs an input packet from the BBP. have.

More specifically, the reception device 51 of FIG. 2 includes a reception unit 71, a BBF descrambler 72, a BBP extraction unit 73, and an input packet generation unit 74. The reception unit 71 receives the BBF transmitted from the transmission device 11 through a network, a broadcasting network, or the like, and supplies it to the BBF descrambler 72.

The BBF descrambler 72 descrambles the scrambled BBF supplied from the receiving unit 71 to obtain a BBF in a non-scrambled state, and supplies it to the BBP extraction unit 73.

The BBP extraction unit 73 is provided with a BBH recognition unit 73a. The BBP extraction unit 73 controls the BBH recognition unit 73a to recognize information of BBH, which is a header of the BBF. The BBP extraction unit 73 extracts BBP from the BBF based on the recognized BBH information, and supplies it to the input packet generation unit 74.

The input packet generation unit 74 restores, generates, and outputs an input packet input to the transmission device 11, which is a transmission source, from the BBP supplied from the BBP extraction unit 73.

[Composition of BBP]

Next, with reference to Fig. 3, the configuration of the BBP generated by the BBP generation unit 31 of the transmission device 11 based on the input packet will be described.

The BBP consists of a header and a data field constituting the BBP payload. In Fig. 3, a header is formed by combining the data field DF constituting the lowermost payload in the figure and the structure excluding the deleted TS packet number unit DNPC described later. The header of the BBP can be used by switching the number of bits for storing the packet length into three types according to the packet length of the BBP.

The header when the input packet has the minimum fixed length is the minimum fixed length header FH1 shown in the second row from the top of the left part of FIG. 3. The minimum fixed length header FH1 consists of 1 byte (8 bits). In addition, the minimum fixed length header FH1 is a 2-bit type identification unit (Type) FH1-1, a 1-bit mode identification unit (Mode) FH1-2, and a 5-bit packet length portion (Length (LSB)). It consists of FH1-3.

The type identification unit FH1-1 indicates the type of the input packet. More specifically, the type identification unit FH1-1, as shown in Fig. 3, identifies the types of four types of input packets with 2 bits. In the example of Fig. 3, when the type identification unit FH1-1 is 00, 01, 10, 11, the type of each input packet is TS-Gp (a group of TS (Transport Stream) packets), and IPv4 (Internet Protocol version 4). ), IPv6 (Internet Protocol version 6), and other (others).

The configuration of the other 6 bits of the minimum fixed length header FH1 varies according to the type identified in the type identification unit FH1-1. That is, when the type identification unit FH1-1 is any one of 01, 10, 11, that is, the type designated by the type identification unit FH1-1 is IPv4, IPv6, and other (other), the upper left corner of FIG. It has the configuration shown in the second step. That is, from the left, it is composed of 1 bit of the mode identification unit FH1-2 indicating whether or not it is in the short packet (SP) mode, and 5 bits of the packet length unit FH1-3 indicating the packet length of the IP packet.

The short packet mode is a mode of the header of the BBP in which the header is composed of only the minimum fixed length header FH1. Here, when the mode identification unit FH1-2 stores 1, it is the short packet mode, and when it stores 0, it is not the short packet mode. For example, when the mode identification unit FH1-2 stores 1, since it is a short packet mode, the header is configured only by the minimum fixed length header FH1, and the data field DF constituting the BBP payload in this minimum fixed length header FH1 BBP is formed by adding

Therefore, in this case, the packet length of the data field DF serving as the payload is expressed by up to 5 bits. However, the actual packet length is the number of bits larger than 5 bits. This is because the packet length is expressed in 5 bits by offsetting by the minimum value of the packet length.

On the other hand, when the mode identification unit FH1-2 stores 0, that is, not in the short packet (SP) mode, and the header is not only the minimum fixed length header FH1, the variable length header VH1 shown in the upper right of FIG. 3 It is added to this minimum fixed length header FH1 to form a header.

The variable length header VH1 consists of 1 byte (8 bits). In more detail, the variable-length header VH1 includes a 6-bit packet length portion (Length (MSB)) VH1-1, a 1-bit flag portion VH1-2, and a 1-bit additional header identification portion (Add Head) It is composed of VH1-3.

The packet length part VH1-1 stores the upper 6 bits indicating the packet length of the BBP. On the other hand, in this case, the lower 5 bits are stored by the 5-bit packet length portion FH1-3 of the minimum fixed length header FH1. Therefore, in this case, the packet length of the BBP is stored as information of 11 bits in total.

For example, the flag unit VH1-2 functioning as a flag stores information indicating the presence or absence of a division mode in which an input packet is divided and a BBP is configured. In more detail, the flag unit VH1-2 stores 0 when the input packet is not in the division mode in which the BBP is configured, and stores 1 in the division mode. In addition, when 1 is stored in the flag portion VH1-2 to indicate that it is in the divided mode, in addition to the variable length header VH1, the flag header VH2 shown in the second row from the top of the right portion of FIG. 3 is added.

The flag header VH2 is composed of 1 byte (8 bits), a 3-bit flag ID unit (Frag.ID) VH2-1 that stores an IP packet serving as a division source, and a 5-bit segmented individual individual It is composed of a Frag Counter VH2-2 that stores a division number for identifying the payload.

For example, the additional header identification unit VH1-3 functioning as a flag stores information indicating the presence or absence of the additional header AH1 or the protocol type header VH3, and stores 0 if the additional header AH1 or the protocol type header VH3 does not exist. And, if present, store 1. In addition, when 1 is stored in the additional header identification unit VH1-3, for example, the additional header AH1 shown in the third row from the bottom of the left part of FIG. 3, or the protocol type header shown in the third row from the top of the left part VH3 is added.

The additional header AH1 is composed of 1 byte (8 bits), and a 2-bit label type part (Label Type) AH1-1, a 5-bit packet length part (Length (E-MSB)) AH1-2 and 1-bit It consists of an extended header identification unit (Ext.) AH1-3.

The Label Type AH1-1 stores information identifying the type of a label additionally stored as a header. The packet length part AH1-2 stores information of the highest 5 bits indicating the packet length of the BBP.

Accordingly, in this case, the packet length of the BBP is stored in the packet length portion FH1-3 of the minimum fixed length header FH1 with the least significant 5 bits, and the 6 bits higher than the lowest order 5 bits are the packet length portion of the variable length header VH1. VH1-1 stores, and the highest 5 bits store the packet length AH1-2 of the additional header AH1. As a result, in the header of the BBP, information on the packet length is stored as 16-bit information.

That is, when expressing the packet length, the first mode including the 5-bit packet length part FH1-3 in the minimum fixed-length header FH1, and 11 added 6 bits of the packet length part VH1-1 in the variable-length header VH1. In a second mode including bits, and a third mode including 16 bits in which 5 bits of the packet length part AH1-2 of the additional header AH1 are further added, the configuration of the header can be changed and set.

As a result, it is possible to adjust the number of bits set in the packet length section in three steps for the header of the BBP according to the packet length of the BBP, so that the number of bits in the packet length section can be increased or decreased as necessary. As a result, it becomes possible to suppress the redundancy of BBP, and it becomes possible to improve the communication speed. In the following, the first mode is also referred to as a short packet mode, the second mode is referred to as a variable length mode, and the third mode is also referred to as an additional variable length mode. In addition, in this example, an example in which three types of bit lengths of 5 bits, 11 bits and 16 bits are set in advance to store the packet length will be described. However, as a bit for storing the packet length, more The number of bits of the type may be set, or redundancy may be further reduced by increasing the number of options in this manner.

Further, the label type unit AH1-1 stores information for identifying the types of four types of labels added to the header in 2 bits, as shown in Fig. 3. More specifically, in the example of Fig. 3, when the label type unit AH1-1 stores 00, 01, 10, and 11, the types of labels to be added respectively are No.Label (no label is added), ReUse (reuse). Reuse of the previous label), 3BLabel (a 3-byte long label), and 6BLabel (6-byte long label) are shown. In addition, the label referred to here is, for example, a Mac address (Media Access Control address) for identifying a device. In addition, when the label type unit AH1-1 stores 10 and 11, that is, when a label having a length of 3 bytes or a length of 6 bytes is added, as shown in the second row from the bottom of the left part of FIG. 3, 3 bytes Alternatively, a 6-byte label header AH3 is added to the rear end of the additional header AH1.

For example, the extended header identification unit AH1-3 functioning as a flag stores information indicating the presence or absence of the extended header AH2. More specifically, the extension header identification unit AH1-3 stores 0 when the extension header AH2 does not exist, and stores 1 when the extension header AH2 exists, and 2 from the bottom of the right side of FIG. As shown in the first step, an extended header AH2 including an arbitrary N1 byte is added to the additional header AH1. Extension Headers AH2 stores arbitrary header information.

In addition, in the minimum fixed length header FH1, when the type identification unit FH1-1 is 11 and the designated type is other than IPv4, IPv6, etc., the protocol shown in the third column from the top of the left part in FIG. 2 bytes of the type header (Protocol Type) VH3 are added.

In addition, when the type identification unit FH1-1 is 00 and the designated information is a TS packet (TS-Gp), the minimum fixed length header FH1 is 6 bits other than the 2 bits of the type identification unit FH1-1, as shown in FIG. It consists of the TS header FH2 shown in the upper left part.

The TS header FH2 is composed of 1 byte (8 bits) in addition to the type identification unit FH1-1, and a 1-bit empty packet identification unit FH2 indicating whether or not it is in a null packet deletion mode in which empty packets are deleted. It consists of -1 and a 4-bit TS packet counting part FH2-3 indicating the number of TS packets constituting the payload of the BBP. In addition, 1 bit is an empty bit (TBD) FH2-2. Here, when generating the BBP, the empty packet identification unit FH2-1 stores 0 when not in the empty packet deletion mode in which empty packets are deleted from the payload, and stores 1 in the empty packet deletion mode. In addition, in the empty packet deletion mode, a deleted TS packet number unit DNPC including one byte, indicating the number of deleted TS packets, is added to the rear end of the data field DF.

In the following, the mode when the input packet is a TS packet will be referred to as a TS mode. In Fig. 3, TS header FH2 is a 4-bit TS packet counting unit FH2-3 indicating the number of TS packets constituting the payload of the empty packet identification unit FH2-1 and the BBP, and an empty bit (TBD) FH2. Although it is shown to be composed of -2, hereinafter, 1 byte including 2 bits of the type identification unit FH1-1 is also referred to as TS header FH2.

[Configuration example of BBF including BBP in variable length mode]

Next, with reference to Fig. 4, a configuration example of the BBF including the BBP in the variable length mode will be described.

As shown at the top of Fig. 4, it is assumed that input packets 101-1 to 101-3 are input. Here, when the input packets 101-1 to 101-3 do not need to be individually distinguished, they are simply referred to as input packets 101, and other configurations are referred to in the same manner. In addition, the input packet 101 is referred to as an IPv4-compatible IP packet, and is referred to as a packet length smaller than 2046 bytes, that is, a packet length that can be expressed by 11 bits in units of bytes.

In this case, by the BBP generation unit 31, for each of the input packets 101-1 to 101-3, as shown in the second row from the top of FIG. 4, the header 121-1 To 121-3) are installed, and BBP (Baseband Packets) 111-1 to 111-3 to which the BBP (Payload) payloads 122-1 to 122-3 are added are generated. Here, the BBP payload 122 is the input packet 101 itself.

In addition, the header 121 has a configuration shown at the bottom of FIG. 4. In addition, in the drawing, the content of the header 121 of the BBP 111 stored in the BBF 131 in the second row from the bottom in the drawing is shown, but the header 121 of the BBP 111 illustrated in the second row from the top. ) And the same configuration.

That is, since the packet length of BBP is the maximum of 2048 bytes, 11 bits are required. For this reason, since the header 121 is in a variable length mode, it is composed of a minimum fixed length header FH1 and a variable length header VH1. More specifically, in the minimum fixed length header FH1, in the type identification unit (Type) FH1-1, the mode identification unit (SP) FH-2, and the packet length unit (LSB Length) FH-3, 01, 0 and Information on the packet length of 5 bits of the input packet is stored. That is, the minimum fixed length header FH1 in FIG. 4 indicates that the input packet is IPv4 and is not in the short packet mode, and information on the packet length of 5 bits is stored as the lower 5 bits of the packet length of the BBP.

In addition, 6 bits, 0 and 0 of the packet length are stored in the packet length portion VH1-1, the flag portion VH1-2, and the additional header identification portion VH1-3 of the variable length header VH1, respectively. That is, the variable-length header VH1 of Fig. 4 indicates that the upper 6 bits of the packet length of the input packet BBP are stored, not in a division mode, and no additional header is present.

Further, the packet lengths FH1-1 and VH1-1 can express the packet length of an input packet of up to 2048 bits that can be expressed in 11 bits.

The BBF generation unit 32 converts the BBP as shown in the second step from the top of FIG. 4 to the BBFs 131-1 and 131-2 as shown in the third step from the top of FIG. 4.

That is, the BBFs 131-1 and 131-2 are composed of headers (BBHs) 141-1 and 141-2 and BBF payloads 142-1 and 142-2, respectively. In addition, the frame length of the BBF 131 is specified by the code length and the code rate. That is, the frame length of the BBF 131 is set according to the code length and the coding rate, for example, as shown in FIG. 5, and the BBF generator 32 is set according to the code length and the coding rate. A frame-length BBF 131 is created.

That is, in FIG. 5, as shown in the left part, the frame length of the BBF 131 is indicated by K_bch. In the table on the right side of Fig. 5, from the left, the coding rate (LDPC code rate) when the BBP is LDPC (Low Density Parity-check Code) coding, the input code length N _ldpc [bits], and the code length after coding K _bch [bits] and the data length K _bch [B] obtained by converting the code length after encoding into bytes are shown, respectively. In the figure, the LDPC code rate is 6/15 to 13/15 from the top, and the code length K _ldpc [bits] is 64800 and 16200 bits from the top. Here, the code length after encoding is the frame length of the BBF 131.

Here, the relationship between the input code length N _ldpc and the code length K _bch after encoding is the relationship shown in the lower left _corner of FIG. 5. That is, the input code length N _ldpc is, BBFRAME (= code length K _bch), BCHFEC inside (the so-called external call forward error correction code FEC (Forward Error Correction)), LDPCFEC (so-called, as shown in the lower left of Fig. 5 FEC) of the heading is included. Thus, the input is a code length N _ldpc is obtained by being encoded according to the code rate, the code length, including a BCHFEC K _ldpc. Further, the frame length is K _bch (= BBFRAME) of BBF (131) shown in the right portion of Figure 5, is the code length after coding, including BCHFEC by subtracting BCHFEC minutes from K _ldpc value. BCHFEC is, will be inputted bit length specified by a N _ldpc, for example, a 192 bit input when the code length N _ldpc is 64800, and a 168-bit when the input code length N _ldpc is 16200.

Thus, for example, a view as indicated in long bold line horizontally in, the input data length K _ldpc is 64800 [bits], if the LDPC coding rate is 10/15, and after encoding the data length K _bch is 43 008 ( =64800×10/15-192)[bits], resulting in 5376[B].

That is, the numerical value in the vertically long thick line frame of the rightmost row in the right part of Fig. 5 is the frame length, and the maximum frame length of the BBF is 6996 [B] in the table of Fig. 5. For this reason, in the header (BBH) 141 of the BBF 131, an address of at least 13 bits is required.

In addition, in the BBF 131 in this way, since the frame length is specified by the code length and the coding rate, as shown in the third row from the top of FIG. 4, the header 141 is the head of the BBP 121 After being stored in, the frame length is stored in the BBF payload 142 in order. As a result, as shown in the third column from the top of FIG. 4, in the BBF 131-1, when the header 141-1 is stored at the start position, the BBP 111-1 is stored immediately thereafter. . In addition, the BBP (111-2) is stored at the rear end, but since the whole cannot be stored, the header (121-2) and one part (122-2-1) of the BBP payload (122-2) are stored as a part. do.

In addition, in the next BBF (131-2), immediately after the header (141-2) is stored at the start position, the other part (122-2-2) of the BBP payload (122-2) is stored, and Later, the BBP 111-3 is stored. The header (BBH) 141 is composed of 2 bytes and stores information of a pointer indicating the head position of the BBP stored in the BBF 131. For this reason, the header 121-2 of the BBF 131-1, the BBP payload 122-2-1, and the BBP stored immediately after the header 141-2 of the BBF 131-2 By combining the payload 122-2-2, it becomes possible to restore the BBP 111-2. In addition, based on the information in the header 141-2, the head position in which the header 121-3 of the BBP 111-3 is stored can be confirmed with a pointer, so that the BBP 111- It becomes possible to properly read 3).

[Specific configuration example of header of BBP in variable length mode]

Next, with reference to Fig. 6, a specific configuration example of the header 121 of the BBP 111 in the variable length mode will be described. Here, the IP packet constituting the input packet 101 is IPv4 (Internet Protocol version 4)/UDP (User Datagram Protocol), and the packet length is assumed to be 1500B. In addition, it is assumed that the input packet is converted into one BBP without division, and there is no addition of an additional header or the like.

That is, as shown at the top of Fig. 6, since the input packet 101 is 1500B, the packet length needs to be at least 6 bits, so that only 5 bits of the packet length part FH1-3 of the minimum fixed length header FH1 can reduce the packet length. Cannot express On the other hand, if 6 bits of the packet length portion VH1-1 in the variable length header VH1 are added, expression in 11 bits becomes possible, and up to 2048 bytes can be expressed. Further, since it is not assumed that the input packet is divided, the header 121 is in a variable length mode, and is composed of 2 bytes including a minimum fixed length header FH1 and a variable length header VH1. Here, the packet length of the BBP is 1502 (=1500+2) bytes as shown in the second row from the top of FIG. 6.

Further, since the input packet 121 is IPv4/UDP, the minimum packet length of an IP packet is 20 bytes, and since the minimum packet length of UDP is 8 bytes, the minimum packet length of the input packet is 28 bytes. Therefore, when expressing the packet length of the BBP 131, 28 bytes are necessarily generated, and thus, it is unnecessary as information for identifying the packet length. Therefore, in 11 bits including 5 bits of the packet length part FH1-3 and 6 bits of the packet length part VH1-1, the minimum packet length of 28 bytes is subtracted from 1502 bytes of the BBP packet length by 1474 bytes. Express the packet length. Therefore, when 1474 expressed as a decimal number is expressed as a binary number, it becomes "10111000010".

According to the above information, since the header 121 is in a variable length mode, it is composed of a minimum fixed length header FH1 and a variable length header VH1 shown at the bottom of FIG. 6. The type identification unit (Type) FH1-1 of the minimum fixed length header FH1 in FIG. 6 stores "01" indicating IPv4, and the mode identification unit (SP) FH1-2 indicating whether or not the short packet mode is in the short packet mode. It stores "0" indicating that it is not. The packet length section (Length MSB) FH1-3 stores "00010" as the lower 5 bits representing the input packet length. Further, the packet length portion (Length MSB) VH1-1 of the variable length header VH1 stores "101110" as the upper 6 bits representing the input packet length. The fragment VH1-2 stores "0" indicating that the division mode is not present, and the additional header identification unit (Add) VH1-3 stores "0" indicating that there is no additional header.

[Configuration example of BBF including BBP in short packet mode]

Next, referring to FIG. 7, an example of the configuration of the BBF including the BBP in the short packet mode will be described.

As shown at the top of Fig. 7, it is assumed that input packets (Input IPv4 Packets) 101-11 to 101-13 are input. Here, it is assumed that the input packets 101-11 to 101-13 are 46 bytes (B), 40 bytes (B), and 50 bytes (B), respectively, for example.

In this case, the headers 121-11 to 121-13 for each of the input packets 101-11 to 101-13 by the BBP generation unit 31 as shown in the second step from the top of FIG. ) Is installed, and BBPs 111-11 to 111-13 to which BBP (Payload) payloads 122-11 to 122-13 are added are generated. Here, the BBP payload 122 is the input packet 101 itself.

In addition, the header 121 has a configuration shown at the bottom of FIG. 7. Here too, the header 121 in the second row from the top and the header 121 in the third row from the top have the same configuration.

That is, since the header 121 is in the short packet mode, it is composed of only the minimum fixed length header FH1. More specifically, in the minimum fixed length header FH1, in the type identification unit (Type) FH1-1, the mode identification unit (SP) FH-2, and the packet length unit (LSB Length) FH-3, 01, 1 and Information on the packet length of 5 bits of the input packet is stored. That is, the minimum fixed length header FH1 in Fig. 7 indicates that the input packet is IPv4 and is in the short packet mode, and stores information on the packet length of 5 bits.

The BBF generation unit 32 converts the BBP as shown in the second step from the top of FIG. 7 to the BBFs 131-11 and 121-12 as shown in the third step from the top of FIG. 7.

That is, the BBFs 131-11 and 121-12 are composed of headers (BBH) 141-11 and 141-12 and BBF payloads 142-11 and 142-12, respectively. In addition, the frame length of the BBF 131 is specified by the code length and the code rate as described with reference to FIG. 5.

As described above, in the BBF 131, since the frame length is set by the code length and the coding rate, as shown in the third row from the top of FIG. 7, the BBP 121 has the BBF payload ( 142). As a result, as shown in the third row from the top of Fig. 7, in the BBF 131-11, when the header 141-11 is stored at the start position, the BBPs 111-11 to 111-13 ) Is saved. However, since the BBP 111-14 cannot store the whole, the header 121-14-14 and the BBP payload 122-14 of the BBP 111-14-1 that are part of the BBP 111-14 A part of the BBP payload 122-14-1 is stored. In addition, the BBF (131-12) is, immediately after the header (141-12) is stored at the start position, the BBP payload (122-14) of the BBP (111-14-2) which is a part of the BBP (111-14). The other part 122-14-2 is stored, and at a later stage, the BBP 111-15 is stored. The header (BBH) 141 is composed of 2 bytes and stores information of a pointer indicating the head position of the stored BBP. For this reason, the header 121-14 of the BBF 131-11, the BBP payload 122-14-1, and the BBP stored immediately after the header 141-12 of the BBF 131-2 By combining the payloads 122-14-2, it becomes possible to restore the BBP 111-14. In addition, based on the information in the header 141-12, the head position in which the header 121-15 of the BBP 111-15 is stored can be confirmed with a pointer, so that the BBP 111- It becomes possible to properly read 15).

[Specific configuration example of header of BBP in short packet mode]

Next, with reference to Fig. 8, a specific configuration example of the header 121 of the BBP 111 in the short packet mode will be described. In addition, the IP packet constituting the input packet 101 here is IPv4 (Internet Protocol version 4)/UDP (User Datagram Protocol), and the packet length is assumed to be 36 bytes.

That is, as shown at the top of FIG. 8, since the input packet 101 is 36 bytes, information on the packet length is required at least 6 bits, but as described above, the minimum packet length of 28B can be offset. For this reason, by adding 1 byte of the header 121, the total packet length becomes 9 bytes, and it becomes possible to express by 5 bits of the packet length part FH1-3. More specifically, if 9 expressed as a decimal number is expressed as a binary number, it becomes 01001.

According to the above information, since the header 121 is in the short packet mode, it is composed of only the minimum fixed length header FH1 shown at the bottom of Fig. 8. The type identification unit (Type) FH1-1 of the minimum fixed length header FH1 in Fig. 8 stores "01" indicating IPv4, and the mode identification unit (SP) FH1-2 indicating whether or not the short packet mode is used is a short packet. "1" indicating that it is in the mode is stored. The packet length section (MSB) FH1-3 stores "01001" as 5 bits representing the length of the input packet.

Further, in the above, since the input packet is IPv4/UDP, an example of offsetting 28B as the minimum packet length has been described, but it is sufficient to offset the minimum packet length according to the type of the input packet. For example, in the case of IPv6/UDP, since the minimum IP packet length is 40 bytes and the minimum UDP packet length is 8 bytes, in this case, 48 bytes as the minimum packet length by 5 bits of the packet length part FH1-3 It can be expressed as an offset value.

[Exemplary configuration of BBP header in additional variable length mode]

Next, with reference to Fig. 9, a specific configuration example of the header 121 of the BBP 111 in the additional variable length mode will be described. In addition, it is assumed that the IP packet constituting the input packet 101 is IPv4 (Internet Protocol version 4)/UDP (User Datagram Protocol), and the packet length is 65533B. In addition, it is assumed that it is not the division mode, and the input packet is converted into one BBP without division.

That is, as shown at the top of FIG. 9, since the input packet 101 is 65533B, the packet length needs to be at least 16 bits, so 5 bits of the packet length part FH1-3 of the minimum fixed length header FH1 and the variable length header VH1 11 bits including 6 bits of the packet length part VH1-1 in VH1-1 are insufficient. Therefore, 5 bits of the packet length part AH-2 of the additional header AH1 are required. For this reason, the additional header identification unit VH1-3 of the variable length header VH1 stores "1" indicating that the additional header AH1 is present.

9, the packet length is 5 bits of the packet length part FH1-3 of the minimum fixed length header FH1, and 6 bits of the packet length part VH1-1 of the variable length header VH1, and Is expressed by a total of 16 bits including 5 bits of the packet length part AH-2 of the additional header AH1. Therefore, it becomes possible to express a packet length of up to 65536 bits. However, as shown in the third row from the top of FIG. 9, 1 byte each of the minimum fixed length header FH1, the variable length header VH1, and the additional header AH1 is included in the packet length. Accordingly, only the header 121 constituting the BBP 111 requires 3 bytes. As a result, as shown in the top of FIG. 9, as an input packet, the maximum packet length that can be represented is 65533B, and as shown in the second row from the top of FIG. 9, the header 121 of the BBP 111 and The sum of the BBF payload 122 can be expressed up to 65536B.

According to the above information, since the header 121 is in the additional variable length mode, as shown in the third row from the top of FIG. 9, it is composed of a minimum fixed length header FH1, a variable length header VH1, and an additional header AH1. The type identification unit (Type) FH1-1 of the minimum fixed length header FH1 in FIG. 9 stores "01" indicating IPv4, and the mode identification unit (SP) FH1-2 indicating whether the short packet mode is in the short packet mode. It stores "0" indicating that it is not. The packet length part (Length LSB) FH1-3 stores the least significant 5 bits representing the length of the input packet.

Further, the packet length portion (Length MSB) VH1-1 of the variable length header VH1 stores 6 bits higher than the lowest 5 bits representing the input packet length. The fragment VH1-2 stores "0" indicating that the division mode is not present, and the additional header identification unit (Add Head.) VH1-3 stores "1" indicating the existence of an additional header. do.

Further, the label type portion AH1-1 of the additional header AH1 stores "00" indicating that no label is added. The packet length section (Length (E-MSB)) AH1-2 stores the highest 5 bits representing the input packet length. The extended header identification unit (Ext.) AH1-3 stores "0" indicating that the extended header AH2 does not exist.

As described above, by the additional variable length mode, the header 121 of the BBP 111 can be set to 3 bytes in total, and redundancy can be suppressed. For example, even in GSE (Generic Stream Encapsulation) and TLV (Type Length Value), the header is set to 4 bytes, and the header of the present technology can be made smaller than this header, so redundancy can be suppressed. .

[Example of header configuration of BBP when split mode is used in variable length mode]

Next, with reference to FIG. 10, an example of the configuration of the header 121 of the BBP 111 when the split mode is used in the variable length mode will be described. In addition, it is assumed here that the IP packet constituting the input packet 101 is IPv4 (Internet Protocol version 4)/UDP (User Datagram Protocol), and the packet length is 65440B.

That is, as shown at the top of FIG. 10, the input packet 101 is 65440 bytes (B). Further, the header 121 of the BBP 111 is a variable length mode, and the BBP 111 is a split mode. Accordingly, 11 bits for expressing the packet length including the packet length portion FH1-3 of the minimum fixed length header FH1 and the packet length portion VH1-1 of the variable length header VH1 are set in the header 121. Accordingly, the maximum packet length of the BBP generated by dividing the input packet 101 is 2048 bytes. Here, the headers 121-1 and 121-2 are the minimum fixed-length header FH1[1], the variable-length header VH1[1], and the flag header, respectively, as shown in the second row from the bottom and the bottom of FIG. 10 It consists of VH2[1], and a minimum fixed length header FH1[2], a variable length header VH1[2], and a flag header VH2[2]. For this reason, 3 bytes are required for each header 121.

Accordingly, the input packet 101 is at most 2045 (=2048-3) bytes. Therefore, in the case of FIG. 10, as shown in the second step from the top, with respect to the input packet 101, 32 (=65440/2045) BBPs 111-1 to 111-32 (after 111-3, Not shown) is generated. Here, in the BBPs 111-1 to 111-32, each of the BBF payloads 122-1 to 122-32 including 2045 bytes in which the input packet is divided into 32 has a header 121 of all 3 bytes. -1 to 121-32) are added. That is, in the example of Fig. 10, all of the BBPs 111-1 to 111-32 have a maximum packet length of 2048 bytes.

According to the above information, since the header 121-1 is a variable-length mode and is a split mode, the minimum fixed-length header FH1[1], the variable-length header VH1[1], and It consists of the flag header VH2[1]. The type identification unit (Type) FH1-1[1] of the minimum fixed length header FH1[1] in Fig. 10 stores "01" indicating IPv4, and indicates whether the short packet mode is in the mode identification unit (SP) FH1. -2[1] stores "0" indicating that it is not in the short packet mode. The packet length section (Length (MSB)) FH1-3[1] stores the lower 5 bits representing the input packet length. Further, the packet length section (Length (MSB)) VH1-1[1] of the variable length header VH1[1] stores the upper 6 bits representing the input packet length. The fragment VH1-2[1] stores "1" indicating that it is in the split mode, and the additional header identification unit (Add) VH1-3[1] indicates that the additional header AH2 does not exist. Save "0". In addition, the flag ID unit VH2-1[1] of the flag header AH2[1] is information for identifying the divided individual payload, for example, since it is a start, "000" is stored, and the flag counter unit VH2-2[1] is a division number for identifying the divided individual payload, and stores "00000" because, for example, the flag counter VH2-2[1] is the start.

Meanwhile, the header 121-2 is shown at the bottom of FIG. 10. In addition, for the header 121-1 and the header 121-2, the description is omitted except that the flag counter VH2-2[2] is different from the flag counter VH2-2[1]. do. That is, the flag counter unit VH2-2[2] stores "00001" as a number following the BBP 111-1.

As described above, by using the division mode, the amount of transmitted packets increases as the header increases, but it becomes possible to divide and transmit the input packet 101 having a long packet length. Therefore, for example, when a packet with a higher priority is to be transmitted first, transmission of the input packet 101 having a longer packet length is temporarily stopped, and the packet with a higher priority is interrupted first, and then, It becomes possible to transmit the divided packet again.

[Configuration example of BBF including BBP in TS mode and not in empty packet deletion mode]

Next, with reference to FIG. 11, an example of the configuration of the BBF including the BBP in the TS mode and not in the null packet deletion mode will be described.

As shown at the top of Fig. 11, it is assumed that input packets 101-31 to 101-33 are input. Here, the input packets 101-31 to 101-33 are, respectively, TS packets 151-1 to 151-8, TS packets 151-11 to 151-18, and TS packets 151-1 to 151- 28). That is, the input packet 101 is composed of all eight TS packets 151, and these are composed of BBF payloads 122-31 to 122-33, and BBPs 111-1 to 111-3 are configured. Has been.

By the way, the TS packet 151 shown in the uppermost part of FIG. 11 is composed of 187 bytes compared to the normal TS packet composed of 188 bytes. As shown at the top of Fig. 12, in general, TS packets 151-1 to 151-8 are sync bytes of 1 byte (0x47) 161-1 to 161 for synchronizing each. -8) is installed, and it contains 188 bytes. Accordingly, for the TS packet 151 shown in the second column of FIG. 11 and the top of FIG. 12, the BBF payload 122 is formed in a form in which the sync byte 161 is deleted. Accordingly, the packet length of the BBF payload 122 is 1496 (=187×8) bytes.

Further, the header 121 has a configuration shown in the lowermost end of Fig. 11 and the lowermost end of Fig. 12. That is, the header 121 is composed of a 1-byte TS header FH2. More specifically, in the TS header FH2, in the type identification unit (Type) FH1-1, the empty packet identification unit FH2-1, and the TS packet number unit FH2-3, "00", "0" and the number of TS packets are respectively. As 4 bits, 8 pieces of "1000" are stored. That is, the TS header FH2 of Fig. 12 indicates that the input packet is a TS packet, not in the empty packet deletion mode, but includes eight TS packets.

The configurations of the BBFs 131-31 and 131-32 are the same as those of the BBF 131 described with reference to FIG. 4, and the description thereof will be omitted.

As described above, in the TS mode, sync bytes are uniformly deleted from the TS packets constituting the BBF payload 122 of the BBP 111. For example, if there are 8 normal TS packets, it becomes 1504 bytes. From 1 byte of the header 121 and 1496 bytes of the BBF payload 122 to 1498 bytes, it becomes possible to compress 6 bytes.

In addition, for example, in the case of DVB-T2, in the TS mode, when there is no concept of BBP and a TS packet as shown in the upper part of FIG. 13 is input, as shown in the lower part of FIG. 13, the BBF 201 A header 211 including 10 bytes (B) of) is installed, and a TS packet excluding sync bytes is stored in the payload 212. Here, the presence or absence of the empty packet deletion mode described later is included in the header 211. For this reason, when transmission of the TS packet is started, the packet of higher priority cannot be transmitted first.

On the other hand, in the TS mode in the present technology, the BBP 111 can be configured, so that even if a packet with a high priority occurs during transmission of the TS packet, it becomes possible to transmit with priority.

[BBP configuration example in TS mode and empty packet deletion mode]

Next, with reference to Fig. 14, an example of the configuration of the BBP in the TS mode and the empty packet deletion mode will be described.

As shown at the top of Fig. 14, input packets are composed of TS packets 151-61 to 151-68, and sync bytes 161-61 to 161 of 1 byte at each head position. -68) is installed. Among these, when the TS packets 151-67 and 151-68 are empty packets, that is, so-called null packets, the BBPs 111-61 are configured as shown in the second row from the top of FIG. 14.

That is, the BBP 111-61 in this case is composed of a 1-byte TS header FH2, as shown in the lower left corner of FIG. 14, and later TS packets 151-61 through 151-66 that are not empty packets. Only is stored, and TS packets 151-67 and 151-68, which are empty packets, are deleted. In addition, as shown in the lower right corner of Fig. 14, a deleted TS packet number unit DNPC (Deleted Null Packet Counter) for one byte indicating the number of deleted TS packets is stored.

Also in this case, the TS packet 151 is stored in a state in which the sync byte is deleted. Therefore, in this example, BBP (111-61) is 1124 (=1+187x6+1) bytes.

Further, the header 121 is composed of a 1-byte TS header FH2, as shown in the lower left corner of Fig. 14. More specifically, in the TS header FH2, in the type identification unit (Type) FH1-1, the empty packet identification unit FH2-1, and the TS packet number unit FH2-3, "00", "1" and the number of TS packets are respectively. As 4 bits, 6 pieces of "0110" are stored. That is, the TS header FH2 in FIG. 14 indicates that the input packet is a TS packet, is in the empty packet deletion mode, and that the BBP 111-61 includes six TS packets.

In addition, as shown in the lower right corner of Fig. 14, a 1-byte deletion TS packet number unit DNPC is set at the rear end of the TS packets 151-66. In this example, the TS packets 151-6 and 151-68 ) Has been deleted, so it is registered as "00000010".

In addition, the TS packet of the empty packet to be deleted is a plurality of TS packets 151 in one BBP 111 only when it is continuously present among the TS packets 151 constituting one BBP 111. Can be deleted. Therefore, in the case of the empty packet deletion mode, when empty packets alternately exist with TS packets 151 that are not empty packets, BBP 111 including one TS packet 151 is configured, and headers ( 121) and deleted TS packet receiving unit DNPC is installed BBP is configured.

However, in the case of DVB-T2, there is also an empty packet deletion mode. In more detail, as shown in the upper part of FIG. 15, when TS packets 151-61 to 151-70 are input, and when TS packets 151-67 and 151-68 are empty packets, FIG. It is configured as shown at the bottom of 15.

That is, for DVB-T2, since there is no concept of BBP in TS mode as described above, the BBF 201 is configured, and information indicating the empty packet deletion mode is stored in a 10-byte header 211. Further, the subsequent payload 212 has a configuration in which a 1-byte deletion packet receiving unit 221 is provided at the rear end of the TS packet 151. In addition, information indicating that two deletions have been deleted is stored in the deletion packet counting unit 221-69 at the rear of the TS packets 151-69 arranged after the TS packets 151-67 and 151-68 are deleted. Therefore, regardless of the presence or absence of a deleted TS packet, a 1-byte deletion packet counting unit 221 is always provided at the rear end of the recorded TS packet 151, and information on the number of deleted TS packets is registered.

On the other hand, in the present technology, since a 1-byte deletion packet receiving unit DNPC is only provided for one BBP, regardless of the presence or absence of deletion, it becomes possible to sufficiently suppress redundancy even when configuring the BBF. In addition, even in the case of transmitting a TS packet, since the BBP 111 can be configured, even if a packet with a high priority occurs during transmission of the TS packet, it is possible to perform interrupt transmission with priority.

[Configuration example of BBP header in bit stream packet]

Next, with reference to FIG. 16, an example of the configuration of the header of the BBP when the input packet is a bit stream packet will be described.

As shown at the top of Fig. 16, it is assumed that a continuous bit stream 301 is input as an input packet.

In this case, the BBP generation unit 31 divides the bit stream 301 in units of 2044 bytes, as shown in the second row from the top of FIG. 16, and headers 121-91 and 121-92 respectively …) is installed, and BBPs 111-91, 111-92… to which BBP (Payload) payloads 122-91, 122-92… including bit streams are added are generated. Here, the BBP payload 122 is a block of the input bit stream in units of 2044 bytes. Therefore, since each BBP 111 is composed of a header 121 of 4 bytes and a BBP payload 122 of 2044 bytes, the packet length is 2048 bytes, which becomes the maximum packet length.

Further, the header 121 has a configuration shown in the lowermost portion of FIG. 16. That is, the header 121 is composed of a minimum fixed length header FH1, a variable length header VH1, and a protocol type header VH3. More specifically, in the minimum fixed length header FH1, in the type identification unit (Type) FH1-1, the mode identification unit (SP) FH-2, and the packet length unit (Length (LSB)) FH-3, 11, 0 and the packet length of the input packet are stored. That is, in the minimum fixed length header FH1 of Fig. 16, it is shown that the type of the input packet is other and not in the short packet mode, and the lower 5 bits are stored as information on the packet length of 5 bits.

In addition, 6 bits, 0 and 1 of the packet length are stored in the variable length header VH1 in the packet length part VH1-1, the flag part VH1-2, and the additional header identification part VH1-3, respectively. That is, the variable-length header VH1 of Fig. 16 indicates that the upper 6 bits of the packet length of the BBP payload as the input packet are stored, not in the division mode, and that an additional header exists. That is, it is shown that the protocol type header VH3 exists as an additional header.

Information on the packet length of the BBP 111 including 11 bits is stored by the packet length portions FH1-1 and VH1-1.

Further, the protocol type header VH3 stores information on the protocol type of a bit stream, which is an input packet including 2 bytes (16 bits).

According to the above information, the header 121 of FIG. 16 is composed of the minimum fixed length header FH1, the variable length header VH1, and the protocol type header VH3 shown at the bottom of FIG. 16. In addition, the type identification unit (Type) FH1-1 of the minimum fixed length header FH1 in FIG. 16 stores “11” indicating other types and indicates whether the short packet mode is in the mode identification unit (SP) FH1. -2 stores "0" indicating that it is not in the short packet mode. The packet length section (Length (MSB)) FH1-3 stores "11111" as the lower 5 bits representing the input packet length. Further, the packet length portion (MSB) VH1-1 of the variable length header VH1 stores "111111" as the upper 6 bits representing the input packet length. That is, in the case of FIG. 16, it is shown that the packet length of the BBP 111 is 2048 bytes, which is the maximum packet length. The flag unit (Flag) VH1-2 stores "0" indicating that the division mode is not, and the additional header identification unit (Add.Head) VH1-3 indicates that the protocol type header VH3, which is an additional header, exists. 1”. The protocol type header VH3 stores information on the protocol type of the bit stream stored in the BBP payload 122.

With such a configuration, it becomes possible to configure and transmit or receive a BBP with various types of bit streams.

Further, as a header compression technique for IPv4 and IPv6, a technique of RoHC (Robust Header Compression) is widely known. RoHC is excellent in compressing the IP header, but in the U-mode (Unidirectional mode), which is complex in processing, has many types, and is suitable for broadcasting, the compression is lower than that of the bidirectional mode, so it is not necessarily implemented. However, in the present technology, it is possible to support RoHC. That is, as shown in Fig. 16 described above, in the type identification unit (Type) FH1-1 of the minimum fixed length header FH1, 11 is stored, information indicating other is registered, and in the protocol type header VH3, By storing RoHC information, it becomes possible to define RoHC as a header. In addition, other than this, it becomes possible to employ various compression methods by the same method.

[Configuration example of BBH of BBF]

Next, a configuration example of the BBH in the BBF will be described with reference to FIG. 17.

For example, the headers 121-101, 121-102, ... as shown at the top of FIG. 17, and BBPs 111-101, which are composed of BBP payloads 122-101, 122-102, ... 111-102, ...) is input, the BBF generation unit 32 generates BBFs 131-1, 131-2 ...) as shown in the second row of FIG. 17.

That is, the BBF generation unit 32, as shown in the second row from the top of FIG. 17, the BBFs 131-1, 131-2, ...) of the data length set according to the packet length and the encoding rate of the input packet. Configure. More specifically, the BBF generation unit 32 stores, for example, the BBH 141-1 at the start position of the BBF 251-1, and at the rear end thereof, the BBP is sequentially set to a BBF of the set data length. Save (111-100, 111-101, …). At this time, as shown in the second column of FIG. 17, when the BBP 111-102 can only be stored until halfway, as much as BBP 111-102-1 is stored until halfway, and the next BBF 131-2 BBH (141-2) is stored at the beginning of, and the rear end of BBP (111-102) is stored as BBP (111-102-2). Then, the BBF generation unit 32 continuously repeats the process of storing the BBPs 111-103, ... until the data length of the BBF 252-2 is reached.

At this time, the BBF generation unit 32 controls the BBH addition unit 41 to set the BBH 141 as shown in the configuration example as shown in the lower right portion of FIG. 17 to the starting position of each BBF 131 Save it to. That is, the BBH 141 is composed of 2 bytes (16 bits), and the BBF 131 of the BBP 111 is stored in a pointer storage unit (Pointer to Start of Next BBP) 321 of 13 bits from the beginning. It stores information of a pointer indicating the starting position of the image. That is, in the case of the second stage of FIG. 17, in the BBH 141-2, in the immediately preceding BBF 131-1, the BBP 111-102-2 that becomes the rear end of the BBP 111-102 that was not stored. ), as indicated by the arrow, the start position of the BBP 111-103 newly stored from the head is stored as a pointer. In addition, 3 bits of the BBH 141 are an empty area (TBD) 322.

By the way, in the BBH of the BBF in DVB-T2, it has the structure as shown in FIG. Here, the upper end of Fig. 18 is a BBH in the case of a normal mode (Normal Mode), and the lower end is a BBH in the case of a high efficiency mode (High Efficiency Mode).

The BBH in DVB-T2 consists of 10 bytes in any mode. In the normal mode, the BBH consists of MATYPE (2 bytes), UPL (2 bytes), DFL (2 bytes), SYNC (1 byte), SYNCD (2 bytes) and CRC-8MODE (1 byte). In addition, in the case of high efficiency mode, BBH consists of MATYPE (2 bytes), ISSY 2MSB (2 bytes), DFL (2 bytes), ISSY LSB (1 byte), SYNCD (2 bytes) and CRC-8MODE (1 byte). do.

MATYPE represents an input stream format, UPL (User Packet Length) represents a user packet length, DFL (Data Field Length) represents a data length in a data field, and SYNC represents a so-called sync byte. In addition, SYNCD refers to the distance from the start position of the data field to the start position of data, CRC-8MODE refers to the mode in CRC-8, and ISSY (Input Stream Synchronization Indicator) LSB and ISSY 2MSB refers to input stream synchronization. Each of the detection information is shown.

That is, in DVB-T2, BBH contains a large amount of data and various types of data. For this reason, not only the processing itself becomes complicated, but also because the data length of the BBH is large, the amount of data circulated also increases.

On the other hand, in the BBH of the present technology, the information stored as described above is only a pointer indicating the start position of the BBP newly stored from the head for each BBF, so it is easy to process after reception at the time of reading, and It becomes possible to suppress

In addition, with such a structure, when the BBP extraction unit 73 in the reception device 51 extracts the BBP 111 from the BBF 131 sequentially supplied, the BBF 131 is simply Based on the information of the BBH 141, it is possible to extract the BBP 111 easily and appropriately since it is only necessary to extract from the head position. As a result, it becomes possible to realize faster and more reliable packet communication.

[Transmit and receive processing by the sending device and the receiving device]

Next, transmission/reception processing by the transmission device 11 of FIG. 1 and the reception device 51 of FIG. 2 will be described with reference to the flowchart of FIG. 19.

In step S11, the BBP generation unit 31 generates the BBP by the above-described processing based on the input packet and supplies it to the BBF generation unit 32. More specifically, the BBP generation unit 31 identifies the type of the input packet, and in the case of an IP packet, the short packet mode described with reference to FIG. 7 and the variable described with reference to FIG. 4 according to the packet length of the input packet. The BBP is generated by either the length mode or the additional variable length mode described with reference to FIG. 9. In addition, when the input packet is a TS packet, the BBP generation unit 31 generates a BBP in the TS packet mode described with reference to FIG. 11 or 14. In addition, when neither an IP packet nor a TS packet, the BBP generation unit 31 registers the recognized type information in the protocol header VH3 as generating BBP from the bit stream packet described with reference to FIG. 15, Generate BBP. Further, the BBP generation unit 31 generates a BBP by generating a header according to a division mode or an empty packet deletion mode as necessary.

In step S12, the BBF generation unit 32 generates a BBF based on the supplied BBP and supplies it to the BBF scrambler 33. In more detail, the BBF generation unit 32 controls the BBH addition unit 41 to generate pointer information indicating the start position of the BBP newly stored from the head for each BBF by the above-described method. Save it to the starting location. In addition, the BBF generation unit 32 generates a BBF by sequentially storing BBPs in the BBF having a frame length set by the code length of the input packet and the code rate, and supplies them to the BBF scrambler 33.

In step S13, the BBF scrambler 33 scrambles the supplied BBF and supplies it to the transmission unit 34.

In step S14, the transmission unit 34 transmits the scrambled BBF to the reception device 51.

In step S31, the reception unit 71 of the reception device 51 receives the BBF transmitted from the transmission device 11 and supplies it to the BBF descrambler 72.

In step S32, the BBF descrambler 72 descrambles the supplied scrambled BBF and supplies it to the BBP extraction unit 73.

In step S33, the BBP extraction unit 73 sequentially extracts BBP from the descrambled BBF. More specifically, the BBP extraction unit 73 controls the BBH recognition unit 73a to recognize information of a pointer indicating the start position of the BBP newly stored from the head for each BBF recorded in the BBH in the BBF. , BBPs in the BBF are sequentially extracted and supplied to the input packet generation unit 74.

In step S34, the input packet generation unit 74 generates an input packet input to the transmission device 11 from the BBP supplied from the BBP extraction unit 73.

In step S35, the input packet generation unit 74 outputs the generated input packet.

Through the above processing, the input packet is converted to the above-described BBP, a BBF is generated based on the converted BBP, and a BBF is transmitted based on the BBF, and a BBP is generated based on the received BBF, and input from the BBP A packet is generated. As a result, redundancy of transmitted/received packets is suppressed, and it becomes possible to realize high speed and reliable packet communication.

In addition, the embodiment of the present technology is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present technology.

For example, each step described in the above-described flowchart can be shared and executed by a plurality of devices in addition to being executed by one device.

In addition, when a plurality of processes are included in one step, a plurality of processes included in the one step can be performed by sharing by a plurality of devices in addition to being executed by one device.

In addition, the present technology can also take the following configuration.

(1) a baseband packet generator for generating a baseband packet from an input packet or stream,

A baseband frame generator for generating a baseband frame from the baseband packet,

Including a transmitter for transmitting the baseband frame,

The baseband packet header includes a minimum fixed length header having type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. Transmitting device including.

(2) When the type identification information is the input packet or the type of the stream is an IP packet, the minimum fixed length header, in addition to the type identification information, identifies whether the input packet length is a minimum fixed length The transmission device according to (1), comprising identification information and minimum input packet length information as information on the input packet length.

(3) when the minimum fixed length identification information indicates that the input packet length is not the minimum fixed length, the header further includes a variable length header in addition to the minimum fixed length header,

The variable-length header includes variable-length packet length information including the high-order bit when the low-order bit of the input packet length is the minimum input packet length and the minimum input packet length information, and the variable-length header The transmission device according to (2), including an additional header flag indicating the presence or absence of an additional header to be added.

(4) When the segmentation flag indicates that a baseband packet is formed by segmenting the input packet or stream,

The transmission device according to (3), wherein the split flag header includes a flag ID for identifying the split flag and a flag counter serving as information for identifying the split baseband packet.

(5) when the additional header flag indicates that the additional header is present, the header further includes an additional header in addition to the minimum fixed length header and the variable length header,

The additional header includes additional header identification information for identifying the type of the additional header, extended packet length information including a bit higher than the variable length packet length information representing the input packet length, and the presence or absence of an additional information header. The transmission device according to (3), including an additional information header flag.

(6) When the additional information header flag indicates that the additional information header is present, the header is the additional information including predetermined information in addition to the minimum fixed length header, the variable length header and the additional header. The transmission device according to (5), further comprising a header.

(7) When indicating that the additional header identification information is label information, the header further includes, in addition to the minimum fixed length header, the variable length header, and the additional header, the additional information header including predetermined label information. The transmission device according to (5) included.

(8) The baseband packet generation unit identifies the type of the input packet or stream, registers the identified type to the type identification unit, and generates a baseband packet according to the identified type. Device.

(9) The transmission device according to (1), wherein the minimum input packet length information is information of a minimum fixed length including bit information obtained by offsetting the number of bits corresponding to the minimum packet size.

(10) When the type identification information is a transport stream packet, the minimum fixed length header, in addition to the type identification information, identifies whether a baseband packet is formed by deleting an empty packet from among the transport stream packets. The transmission device according to (1), comprising: empty packet deletion information to be performed, and transport stream packet number information indicating the number of transport stream packets as information on the length of the input packet included in the baseband packet.

(11) When the packet deletion information is information indicating that a baseband packet is formed by deleting empty packets from among the transport stream packets, the header further includes information indicating the number of deleted empty packets. The transmission device according to (10).

(12) The type identification information includes unspecified protocol information indicating that it is a protocol other than information specifying a protocol of the input packet or stream,

The transmission device according to (1), wherein, when the type identification information is the unspecified protocol information, the header further includes, in addition to the minimum fixed length header, predetermined protocol information specifying a predetermined protocol.

(13) generate a baseband packet from the input packet or stream,

Generating a baseband frame from the baseband packet,

And transmitting the baseband frame,

The baseband packet header includes a minimum fixed length header having type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. Transmission method to include.

(14) a receiving unit that receives a signal including a transmitted baseband frame,

A baseband packet generator for generating a baseband packet from the received baseband frame,

Including an input packet generator for generating an input packet or stream from the baseband packet,

The baseband packet header includes a minimum fixed length header having type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. A receiving device comprising.

(15) receiving a signal including a transmitted baseband frame,

Generate a baseband packet from the received baseband frame,

Generating an input packet or stream from the baseband packet,

The baseband packet header includes a minimum fixed length header having type identification information for identifying the type of the input packet or stream, and information on the packet length of the input packet or stream stored in the payload of the baseband packet. Including receiving method.

11: transmitting device
31: BBP generation unit
32: BBF generation unit
33: BBF scrambler
34: transmitter
41: BBH Bugaboo
51: receiving device
71: receiver
72: BBF descrambler
73: BBP extraction unit
73a: BBH recognition unit
74: input packet generator

Claims (11)

As a receiving device,
Receive a transmitted signal including a first packet having a header and a payload; And
Circuitry configured to generate a first input packet and a second input packet based at least on a header of the first packet, the header of the first packet:
Type identification information indicating a type of the first and second input packets, and
The number of input packets stored in the payload of the first packet
Including,
The first packet includes first information indicating whether or not second information is present,
The second information represents the number of deleted null input packets, and
If the second information does not exist, the empty input packet is not deleted. The method of claim 1,
The receiving device, wherein the type of the first and second input packets is a transport stream packet. The method of claim 2,
A receiving device, wherein a part of the generated first input packet is not included in the first packet. The method of claim 3,
The receiving device, wherein a portion of the generated first input packet not included in the first packet is a portion of a header of the generated first input packet. The method of claim 4,
The receiving device, wherein a portion of the generated second input packet corresponding to a portion of the generated first input packet not included in the first packet is not included in the first packet. As a method,
Receiving a transmitted signal including a first packet having a header and a payload; And
Generating a first input packet and a second input packet based on at least a header of the first packet
Including, the header of the first packet is:
Type identification information indicating a type of the first and second input packets, and
The number of input packets stored in the payload of the first packet
Including,
The first packet includes first information indicating whether or not second information is present,
The second information represents the number of deleted empty input packets, and
If the second information does not exist, the empty input packet is not deleted. The method of claim 6,
The type of the first and second input packets is a transport stream packet. The method of claim 7,
A portion of the generated first input packet is not included in the first packet. The method of claim 8,
The portion of the generated first input packet that is not included in the first packet is a portion of a header of the generated first input packet. The method of claim 9,
A portion of the generated second input packet corresponding to a portion of the generated first input packet not included in the first packet is not included in the first packet. A computer-readable recording medium storing computer-executable instructions,
The computer-executable instructions, when executed by a computer, cause the computer to:
Receiving a transmitted signal including a first packet having a header and a payload; And
Generating a first input packet and a second input packet based on at least a header of the first packet
To perform a method including, the header of the first packet is:
Type identification information indicating a type of the first and second input packets, and
The number of input packets stored in the payload of the first packet
Including,
The first packet includes first information indicating whether or not second information is present,
The second information represents the number of deleted empty input packets, and
If the second information does not exist, the empty input packet is not deleted.

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